This invention relates to an electric distribution box in which female-female terminals for electrically and mechanically connecting connection terminals of bus bars, distribution parts, etc., are received and supported in a case or a plate such as a board.
In many electric connection equipments of the type in which high voltage is dealt with within a limited space, electric wiring within the equipment is formed by installing strip-like bus bars. One example of such equipments is an electric distribution box.
For example, in a hybrid car, an electric car, a fuel cell car or the like, a battery, an ignition switch, an inverter, etc,. are provided via this electric distribution box, and an electromagnetic relay is operated based on an output signal from the ignition switch, and main power is transmitted to the inverter while a voltage sensor detects the condition of the battery (see, for example, JP-A-2004-282908 (Page 1, FIG. 1)).
One example of the construction of such electric distribution box will be described. For example, as shown in FIG. 7, the electric distribution box comprises a lower case z1 having distribution part-receiving portions (not shown) respectively receiving distribution parts (such as fuses, an electromagnetic relay and a pressure sensor) and recess portions z2, bus bars z4 each installed on the lower case z1 and having a connection terminal z5 received in an upstanding manner within the corresponding recess portion z2, female-female terminals z3 which are completely received within the respective recess portions z2, and grip the respective connection terminals z5, and an upper case z6 which is detachably fitted on the lower case z1, and has external connection terminal-inserting holes z7 for the passage of external connection terminals of the distribution parts, etc., therethrough. As described above, for example, main power is transmitted to the inverter or the like by the ON/OFF operation of the ignition switch.
In the related electric distribution box, the upper case z6 is fitted on the lower case z1 having the female-female terminals completely received with the respective recess portions z2 as described, and therefore the following problems have been encountered.
Namely, there are occasions when the external connection terminal-inserting hole z7 and the corresponding female-female terminal z3 are slightly displaced out of registry with each other from some cause, so that the external connection terminal can not be easily inserted into the female-female terminal z3.
For example, when the upper case is caused to strike against a working table or the like, the external connection terminal-inserting hole z7 and the corresponding female-female terminal z3 are slightly displaced out of registry with each other.
In such a case, the worker again carefully inserted the external connection terminal into the female-female terminal, and therefore there has been room for further improvement.
And besides, the side surfaces of the related female-female terminal are flat, and therefore there are occasions when the female-female terminal is inserted in a wrongly-oriented manner into the recess portion. In this case, the external connection terminal-inserting hole and a holding portion of the corresponding female-female terminal are completely displaced out of registry with each other, so that the external connection terminal, in some cases, has failed to be connected to the female-female terminal.
Therefore, as shown in FIG. 8, there has been proposed an electric distribution box in which external connection terminal-inserting holes z10 for the passage of external connection terminals of distribution parts, etc., therethrough are formed in an upper case z9, and recess portions z11 for respectively receiving female-female terminals z3 are formed on this upper case in surrounding relation respectively to the peripheries of the holes z10, thereby preventing a holding portion of the female-female terminal z3, received in each recess portion z11, from being brought out of registry with the corresponding external connection terminal-inserting hole z10.
In the above electric distribution box, although the misregistration of the holding portion of each female-female terminal z3 relative to the external connection terminal-inserting hole z10 can be prevented, the following problem is encountered.
Namely, an upper surface of a lower case on which a plurality of bus bars are installed is flat, and therefore the shortest distance (that is, the creeping distance measured along an insulating surface) between the two conducting members, that is, each female-to-female terminal z3 and each of those bus bars (other than the bus bar to which this female-female terminal z3 is connected) disposed near to this female-female terminal z3, becomes smaller as compared with the related structure in which the recess portions are formed on the upper surface of the lower case, and as a result a problem has arises with the insulating performance.